Molecular recognition studies on supramolecular systems (XXX) - Inclusion complexation of the novel amino acid modified beta-CDs with TNS

The fluorescence spectra have been studied in phosphate buffer aqueous solu tion (pH = 7. 20) to give the stability constants (K-s) for the supramolecu lar system formed by L-Pro-beta-CD (1), L-Leu-beta-CD (2), and L-Ileu-beta- CD (3) with TNS, The results obtained indicate that the binding ability of modified beta-cyclodextrins (1) with TNS is larger than that of 2 and 3, On e possible explanation is that there are different substitutes among the th ree modified beta-cyclodextrins, The molecular binding ability is discussed from the size-fit concept between the host and the guest molecules, The re sults indicate that the substitute on the side arm attached to the edge of beta-CD plays a crucial role in guest inclusion.